JPH0689048B2 - Stirring tower type polymerization reactor - Google Patents

Description

The present invention relates to a high-performance polymerization reactor for continuously producing a polymer.

More specifically, the present invention relates to a continuous polymerization reaction apparatus whose main object is homogenized solution polymerization and bulk polymerization for increasing the viscosity.

[Conventional technology]

As a polymerization mode for producing a polymer, a solution polymerization method and a bulk polymerization method have been frequently used. In the solution polymerization method or the bulk polymerization method, when the polymer is dissolved in a monomer or a solvent, it becomes a homogeneous liquid phase system and becomes a highly viscous fluid as the polymerization reaction progresses.

As the polymerization reaction taking the above-mentioned form, bulk polymerization of polymethylmethacrylate, solution and bulk polymerization of acrylonitrile / styrene resin, solution polymerization of acrylonitrile / butadiene / styrene resin, solution polymerization of polybutadiene, solution of styrene / butadiene rubber. Polymerization, heavy duty operation of nylon 6 using ε-caprolactam as a raw material (especially the final step), polycondensation of nylon 66 using adipic acid and hexamethylenediamine as a raw material (especially the intermediate step), solution polymerization of polyvinyl acetate, etc. is there.

Regarding the functions generally required for continuous polymerization reactors with high viscosity fluids, Yasuhiro Murakami has described in detail in the literature (Basics and analysis of polymerization reactors, Baifukan, 1976).
If you select from the contents, you can list the following items.

(1) The residence time distribution in the flow direction is sharp.

That is, it has a piston flow property.

(2) High uniformity in temperature and concentration (mixing performance) in each region in the flow direction.

(3) There is no poor flow area (dead space) over the entire reactor.

(4) The power required for stirring is low.

(5) A large heat transfer area for removing reaction heat and a high heat transfer coefficient.

(6) The device shape is simple and easy to clean.

Attempts have been made so far to satisfy these functions as much as possible, and numerous polymerization reactors have been proposed. However, a satisfactory one has not been obtained yet.

[Problems to be solved by the invention]

To give an example of a continuous polymerization reactor proposed hitherto, in the case of the model device of JP-A-54-127489, the power required for stirring is large, the heat transfer area is small, and the device shape is complicated. ing. Further, in the case of the reactor described in JP-A-53-99290, there is a problem in piston flowability. Furthermore, in the case of the reactor described in JP-A-60-202720, the structure is complicated because it is biaxial. There are various problems in the continuous polymerization reaction apparatus proposed in the past. The present invention has been made in view of the present situation, the residence time distribution is narrow, that is, there is a piston flow property, the mixing effect is large in each stirring area in the flow direction, there is no flow failure portion, and the required power for stirring is low, It is an object of the present invention to provide a stirring tower type polymerization reaction device having excellent heat conductivity and a simple device structure.

[Means for solving problems]

The present invention provides a cylindrical container having a liquid supply port and a liquid discharge port, a rotary shaft inserted into the container coaxially with the axis of the container, and a plurality of sets attached to the side surface of the rotary shaft. A stirring means composed of a flat plate blade whose axis is parallel to the axis of the rotary shaft and an inclined blade which is attached to the flat plate blade so as to be inclined with respect to the rotary shaft axis, and the same stirring. The present invention proposes a stirring tower type polymerization reaction device, characterized in that it comprises a partitioning means interposed between the means and the stirring means to partition the container in the longitudinal direction.

[Work]

In the reaction apparatus having such a configuration, the liquid is supplied into the container through the liquid supply port and introduced into the stirring area partitioned by the partition means in the longitudinal direction. In this stirring area, the flat blade and the inclined blade that are stirring means attached to the rotating shaft rotate,
Due to the cumulative action, a circulating flow such as an upward flow, a downward flow, and a horizontal flow is generated, and the liquid is sufficiently agitated and mixed by the agitating and mixing action, and is sequentially sent to the next agitating zone to receive the same action while receiving the same action. It is discharged from the liquid outlet to the outside of the system.

〔Example〕

Examples of the stirring tower type polymerization reaction device according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a vertical sectional view of a reaction apparatus according to an embodiment of the present invention.

In FIGS. 1 and 2, a rotary shaft 5 is inserted into a container 4 having a liquid supply port 1, a liquid discharge port 2 and a jacket 3, and the rotary shaft 5 is rotatably supported by a shaft sealing portion 6. It is sealed. The inside of the container 4 is divided by a multi-stage baffle plate 7 which is a partitioning means, and thereby a piston flow property is generated in the flow direction. As the baffle plate 7, a perforated plate having a constant aperture ratio is used. In each stirring chamber 8 divided by the baffle plate 7,
A stirring means is attached to the rotating shaft 5. This stirring means is a combination of a flat plate blade 9 whose plane is parallel to the axis 30 of the rotary shaft 5 and the flat plate blade 9, and the flat plate blade 9 and multiple inclinations on the side surface of the rotary shaft 5 in a horizontal plane. The blades 10 are mounted at positions 90 degrees apart from each other and at positions whose heights are sequentially shifted in the axial direction, and are tilted in the same direction and the same inclination angle with respect to the axis 30 of the rotary shaft 5 as shown in the figure. The inclined blades 10 (a), 10 (b), and 10 (c) are attached to each other and are substantially rectangular and plate-shaped.

FIG. 2 shows a cross section taken along the line II-II in FIG. The flat blade 9 moves in the direction of arrow 11 by the rotation of the rotary shaft 5, and the fluid displaced by this movement becomes a large circulation flow in the inner peripheral portion as shown by arrow 12. The flow velocity of this circulating flow is higher than the moving speed of the inclined blades 10 (a), 10 (b), 10 (c), and rotates past the inclined blades 10 (a), 10 (b), 10 (c). Therefore, the relatively circulating fluid is pushed up by the inclined blades 10 and moves upward. On the other hand, the fluid in the vicinity of the wall surface of the container is affected by the viscous resistance from the wall surface, and only moves slowly in the circumferential direction as shown by the arrow 13, and thus is pushed down by the movement of the inclined blades 10,
Move down. In this way, an ascending flow is generated at the inner peripheral portion and a downward flow is generated at the outer peripheral portion, whereby a vertical circulation flow is formed. In addition, when the inclined blades are attached in a direction opposite to that shown in the drawing, a downward flow is generated in the inner peripheral portion and an upward flow is generated in the outer peripheral portion.

As described above, in the stirring chamber 8, the horizontal circulating flow and the vertical circulating flow are simultaneously generated, so that a good mixed state can be obtained.

Further, also in the corner portion of the stirring chamber 8, the stirring effect of the flat plate blade 9 is well distributed, and it does not become a poor flow region.

In the case of a normal stirring blade, since the flow around the rotary shaft is poor, gel substances and the like are often attached, but in the case of the reaction apparatus of the present embodiment, along the rotary shaft 5 The formation of a deposit is prevented because a strong circulating flow is formed.

As described above, the large flat blade 9 has a role of generating a circulating flow in the horizontal direction, so that its size has an appropriate range. In FIG. 2, in the front part of the flat plate blade 9 in the rotation direction, the flat plate blade 9 moves in a positive pressure state by removing the fluid, and in the rear part, the space generated by the movement of the flat plate blade 9 is filled. Since the circulating flow flows in, a negative pressure state occurs. As described above, since a pressure difference is generated between the front and rear portions of the flat plate blade, a flow that short-circuits the gap between the end portion of the flat plate blade 9 and the container inner wall 31 is generated. Since the circulating flow decreases and the stirring effect decreases in proportion to the increase in the short circuit flow, it is necessary to suppress the short circuit flow as much as possible. From the results of various experiments, the inventors have found that in order to effectively generate a circulating flow, the area surrounded by the shaft core 30 and the outer edge of the flat plate blade 9 is the shaft core 30 of the rotating shaft, the container inner wall 31, and the obstruction. 60% or more of the area surrounded by the plate 7, preferably 80
It has been found that it should occupy more than one percent.

Next, the power required for stirring is equivalent to a normal large paddle blade,
It belongs to the category of low power as a stirring blade for high viscosity fluid. Regarding the heat transfer coefficient of the wall surface, due to the scraping effect of the large flat plate blade and the effect of exchanging the fluid due to the generation of the vertical circulation flow, a heat transfer coefficient higher than that of a stirring blade for a normal high viscosity fluid can be obtained.

Regarding the simplicity of the structure, it is equivalent to a paddle and an anchor blade, and has a simpler structure than the helical ribbon blade that is often used for stirring high-viscosity fluid and the stirring blades proposed in the above-mentioned conventional patent application. is there.

As described above, the reactor of the above-mentioned example fulfills all the functions required for the above continuous polymerization reactor.

In the above embodiments, the case where the baffle plate is a perforated plate is shown, but a concentric ring or the like having an arbitrary shape and structure can be used.

FIG. 3 is a vertical cross-sectional view of a reaction apparatus according to another embodiment of the present invention, and FIG. 4 is a horizontal cross-sectional view taken along the line IV-IV of FIG.

In the case of this embodiment, two flat plate blades 9 (a) and 9 (b) whose surfaces are parallel to the axis 30 of the rotating shaft 5 are mounted on the side surface of the rotating shaft 5 at a distance of 180 ° on the horizontal plane. ing. In addition, two inclined blades 10 (a), 10 (b), 10
(C) and 10 (d) are flat blades 9 (a) and 9 on the side surface of the rotary shaft 5.
It is also mounted at a position 90 ° apart from (b) in the horizontal plane even if it is tilted with respect to the axis 30 of the rotary shaft 5 at the same direction and the same tilt angle as shown in the figure.

Thus, the reactor according to the present invention is not limited by the number of flat blades and inclined blades. Further, partition means is provided between the stirring chambers 8, and the partition means is the tube sheet 20 and the shell.
This is a heat exchange part composed of the tube 21 and the tube 22.
It can be heated or cooled with a heat carrier oil or the like circulating in 21. The tube 22 also functions as a baffle at the same time as heat exchange.

FIG. 5 is a vertical cross-sectional view of a reaction apparatus of still another embodiment of the present invention, and FIG. 6 is a horizontal cross-sectional view taken along the line VI-VI of FIG.

In the case of this embodiment, one flat plate blade 9 and a spiral inclined blade
10 shows a stirring means in which 10 are combined, and shows that the reaction device according to the present invention is not limited to a flat blade. A coil-shaped tube 22 is inserted in the partitioning means between the stirring chambers 8 and heating medium oil or the like is flown into the tube to heat or cool the high-viscosity liquid passing therethrough. At the same time, it has a baffle function.

The experimental results of the residence time distributions of the polymerization reactor of the present invention and the conventional polymerization reactor will be described below.

In this experiment, a flow test device was used in which a long cylindrical container made of a transparent acrylic resin having an inner diameter of 200 mm was divided into eight stirring sections and seven heat exchange sections. In this experiment, various stirring blades attached to this test device were replaced.

The height of the stirring section is 100 mm, and the heat exchange section is equipped with four acrylic resin tubes with an inner diameter of 23 mm and the height is 100 mm. The combination of these is almost the same as the apparatus of FIG.

A 200 poise starch syrup was used as a sample, and a gear pump was used to supply the starch syrup from the bottom of the container. In the middle of continuously supplying starch syrup, pulse syrup colored with red ink is injected,
The flow state was observed with the naked eye, the change with time in the outlet concentration was measured, and the residence time distribution was obtained.

Table 1 shows the types of stirring blades used and the observation results of the flow state at that time. In the table, the comparative example shows the case of the conventional reactor, and the experimental example shows the case of the above-mentioned embodiment.

It is clear from Table 1 that:

(1) In the case of the conventional stirring blade type large paddle and helical ribbon blade, there was a flow failure region.

(2) Examples 1 to 2 using the blade type according to the present invention
No poor flow area was observed in. FIG. 7 shows the measurement results of the residence time distribution of starch syrup in the cylindrical container in the comparative example and each example. In FIG. 7, E (φ) on the vertical axis is the residence time distribution function, and φ on the horizontal axis is the dimensionless time.

In the case of Comparative Example 1, the peak height and position are largely deviated from the perfect mixing tank row model, and it is found that the amount of fluid that stays for a long time is abnormally large, which is not a preferable state.

In the case of Comparative Example 2, the peak height is low, and the equivalent number of tanks in the perfect mixing tank example model is a small value, and the peak distance is far from the piston flow. It is considered that this is because the vertical circulation flow is larger than an appropriate value, and therefore some of the fluid tends to short-pass from the inlet to the outlet.

Examples 1 to 3 have very preferable residence time distributions close to the complete mixing tank row model.

〔The invention's effect〕

The reaction apparatus according to the present invention has the following special remarkable effects, and the present invention provides an industrially useful stirring tower type polymerization reaction apparatus.

(1) Since the reactor according to the present invention is provided with the partition means between the stirring means, it has a piston flow property in combination with a unique stirring effect, and the reaction mixture is stirred according to the progress of the polymerization reaction. The temperature can be controlled separately for each area. Further, when the heat exchange tube is inserted into the partition means, it becomes easier to separately adjust the temperature for each stirring area.

(2) Since the reactor according to the present invention is provided with two types of stirring blades, a flat blade and an inclined blade, on the rotating shaft, a highly viscous liquid or slurry-like substance is rapidly flown upward in the stirring area. By forming a circulating flow of downward flow and horizontal flow, high mixing performance can be achieved and there is no flow failure part.

(3) In the conventional reaction apparatus, since the flow around the rotating shaft for stirring was poor, gel-like substances and the like frequently adhered.
In the reactor according to the present invention, the mixing performance is good, and therefore gel-like deposits are not generated.

(4) Since the reactor according to the present invention is provided with two types of stirring blades, a flat blade and an inclined blade, the required stirring power is smaller than that of a reactor having only flat blades.

(5) The heat transfer coefficient is large and the heat transfer is excellent due to the scraping effect of the flat blades and the effect of fluid exchange due to the generation of the vertical circulation flow.

(6) The device structure is simple.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a reaction apparatus according to an embodiment of the present invention,
1 is a transverse sectional view taken along the line II-II of FIG. 1, FIG. 3 is a longitudinal sectional view of a reactor of another embodiment of the present invention, and FIG. 4 is a sectional view of FIG.
Fig. 5 is a cross-sectional view taken along line IV-IV, Fig. 5 is a vertical cross-sectional view of a reactor according to still another embodiment of the present invention, and Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5, The figure is a graph showing the residence time distributions of the experimental example of the present invention and the comparative example. 1 ... Liquid supply port, 2 ... Liquid discharge port, 3 ... Jacket 4 ... Container, 5 ... Rotating shaft, 7 ... Baffle plate 8 ... Stirring part, 9 ... Plate blade, 10 ... Inclination Wings 20 …… Tube plate, 21 …… Shell, 22 …… Tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Setsuo Omoto 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute (72) Inventor Kazuto Kobayashi Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture 4-6-22 Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Takao Yamazaki 24-10 Matsufudai, Midori-ku, Yokohama-shi, Kanagawa

Claims (1)

[Claims] 1. A cylindrical container having a liquid supply port and a liquid discharge port, a rotary shaft inserted into the container coaxially with the axis of the container, and a plurality of sets on the side surface of the rotary shaft. An agitating means provided with a flat blade and a flat blade whose surface is parallel to the rotary shaft of the same rotary shaft, and a slanting blade that is mounted obliquely with respect to the rotary shaft. A stirring tower type polymerization reaction device, comprising: a stirring means interposed between the stirring means and a partitioning means for partitioning the container in the longitudinal direction.